1. Field of the Invention
The invention presented is directed toward a variable geometry rhomboid wing aircraft with a mechanical or powered torsion bar to control aeroelastic twist and deflection to produce an aerodynamic body.
2. Description of the Related Art
Control of wing and stabilizer surfaces is essential to controlling the direction of flight of an aerodynamic body. For most aircraft, a system of elevators, a rudder, flaps and slats, and ailerons are used to control the movement of the aircraft. Fine maneuverability and banking flight is enabled by ailerons, which can be manipulated to alter the lift and drag for each wing. Alternatively, a wing may be warped to change its aerodynamic properties and obtain similar effects as with ailerons. The Wright Brothers employed a system of bell cranks and pulleys to warp the wing to obtain a fine degree of flight control and banking turns. Today, as new stronger and more flexible composite materials have become available, wing warping is once again becoming a more practicable approach to controlling flight of an aerodynamic body.
Torsion bars, which can be placed along the length of the wing and connected to the wing tip, are an alternative to the Wrights' bell cranks and pulleys as a means for warping a wing to change its aerodynamic properties. U.S. Pat. No. 5,681,014, which is herein incorporated by reference, teaches the use of a torque tube mounted internally in a wing to produce a helicoidal twist with a maximum deflection at the wing tip, to provide increased lateral roll control, lift, braking and maneuverability. Additionally, torsion bars allow flexible wings to stiffen against forces that would cause wing rotation at high flight speeds. U.S. Pat. No. 4,330,100, which is herein incorporated by reference, teaches a wing twist control mechanism comprising a torque tube, which assists high aspect ratio wings to actively compensate for changes in the aerodynamic loads that affect wing twist.
In addition to controlling the lift and drag of surfaces by warping a wing or attenuating ailerons, an aerodynamic body is also affected by the aspect ratio, which affects the overall lift to drag ratio. Aspect ratio is equal to the wing span2/wing area. Thus a longer wing span results in a greater lift to drag ratio of the aerodynamic body. Wing sweep angle is another important aspect in the design of an aerodynamic body. Wings with a lesser sweep angle (i.e., less swept back) have greater lift. Wings having a greater sweep angle, while having less lift, will delay undesirable compression effects at speeds close to the speed of sound. Variable geometry wings are a solution to allowing optimal lift at low air speeds and optimal stability at near sound speeds.
Variable geometry rhomboid wing aircraft are a type of joined wing concept where the two forward wings are swept back, while the rear wing is swept forward. Each pair of forward and rear wings on the same side are then joined at a point along the wing surface and form a triangular shape from the two wings and the section of the fuselage between the wings. The angles in this triangle are allowed to vary by making either of both of the wing mounts variable in position on the fuselage. This type of wing assembly has improved aerodynamic properties as some flight control parameters can be adjusted during flight by varying the wing positions. U.S. Pat. No. 5,899,410, which is herein incorporated by reference, teaches an aerodynamic body having coplanar joined wings forming a rhomboid wing.